机不可失碰上适合的机缘绝不可错失。形容办事要抓住机遇当仁不让。例机不可失,时不再来。英Don't let slip an opportunity; A golden opportunity is not to be missed; Now or never!(谚); Occasion knoks but once;
不可终日一天也过不下去。形容内心极度不安或局势极为紧迫。英be in a desperate situation; be unable to carry on even for a single day;
不可救药病重到已无法用药医治比喻人或事物坏到无法挽救的地步。例惜其乱势已成,不可救药。——《宋史钦宗纪赞》英at the point of death; be a gone (hopeless) case with sb.; beyond (past) cure (hope);